I've been serving my personal website from CloudFront (Amazon's CDN) for years, which was nice because it costs a few cents a month, but it annoyed me that cache misses get served slowly from S3. In some cases, this can take several hundred milliseconds. Completely unacceptable!
I finally decided to look up if anyone would let me serve all of my files from the CDN all of the time, and apparently Bunny CDN[1] does. It's "expensive" (over 10 cents per GB per month!), but since my entire website is ~30 MB, I just told them to store the entire thing on SSDs in every edge region.
Result: Every page loads in ~40 ms from anywhere remotely near an edge location[2], regardless of how recently anyone else has requested the page.
My "unacceptable" above is mostly tongue-in-cheek, but there really is something nice about every link loading instantly rather than in half a second.
The code to do this is also much simpler since Bunny CDN has a CLI that handles sync properly, and cache "misses"[3] are so fast that I'm just not hot caching HTML pages.
I assume there are other options for this, but this is the one everyone talks about and it's going to cost me like $0.10/mo, so I didn't look very hard for alternatives.
There's two layers of lookups in a CDN: The CDN edge (hot cache) and the origin (usually slow). With Bunny CDN + Bunny storage, the origin is on an SSD in the same region, so a cache miss only takes a few milliseconds to load into the hot cache.